﻿/*
* Copyright (c) 2010-2012 Tesla Engine Group
* 
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
* 
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* 
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/


using System;

namespace Tesla.Content {
    /// <summary>
    /// Special content loader that returns the system's "default" resource for a particular content type.
    /// </summary>
    public abstract class DefaultResource {
        private Type _targetType;

        /// <summary>
        /// Gets the target type of the default resource.
        /// </summary>
        public Type TargetType {
            get {
                return _targetType;
            }
        }

        /// <summary>
        /// Creates a new DefaultResource.
        /// </summary>
        /// <param name="targetType">Type of object that will be created.</param>
        protected DefaultResource(Type targetType) {
            _targetType = targetType;
        }

        /// <summary>
        /// Loads the default resource.
        /// </summary>
        /// <param name="type">Target type</param>
        /// <returns>The default resource</returns>
        public abstract Object Load(Type type);
    }

    /// <summary>
    /// Special, strongly-typed content loader that returns the system's "default" resource for a particular content type.
    /// </summary>
    /// <typeparam name="T">Target type</typeparam>
    public abstract class DefaultResource<T> : DefaultResource  {

        /// <summary>
        /// Creates a new DefaultResource.
        /// </summary>
        protected DefaultResource() : base(typeof(T)) {}

        /// <summary>
        /// Loads the default resource.
        /// </summary>
        /// <param name="type">Target type</param>
        /// <returns>The default resource</returns>
        public override Object Load(Type type) {
            if(!TargetType.IsAssignableFrom(type)) {
                throw new InvalidCastException(String.Format("Invalid type, cannot load specified type: {0}, expected type: {1}.", type.FullName, TargetType.FullName));
            }

            return Load();
        }

        /// <summary>
        /// Loads the default resource.
        /// </summary>
        /// <returns>The default resource</returns>
        public abstract T Load();
    }
}
